This invention relates to the mounting of an optical sight to a rail on a receiver of a weapon, and, more particularly, to limiting the torque and force that can be applied in the mounting.
Optical sights utilizing enlarging optics and/or specialized optics such as an infrared imager can be mounted to a hand-held, shoulder-supported weapon such as a rifle. The optical sight is mounted with its optics directed generally parallel to the barrel of the weapon to provide rough sighting of the rifle toward a target. Fine adjustments are made using adjustment features built into the optical sight itself.
The weapon has a rail built into its receiver that extends as closely parallel to the barrel as possible. The optical sight has a corresponding mount with an engagement to the rail such as a slot. To mount the optical sight to the rifle, the slot of the optical sight is engaged to the rail on the weapon receiver. The optical sight is moved forwardly or rearwardly along the receiver by sliding the engagement on the rail, to a position that is serviceable and comfortable for the user of the rifle. A set screw extending between the rail and the optical sight mount is tightened so that the optical sight will not slide along the rail during service.
This type of mounting arrangement is widely used on sporting and military weapons, and for both rifles and pistols. While operable for many applications, it has drawbacks in other situations. When the set screw is tightened, lateral forces are created between the weapon receiver and the optical sight. Because the weapon receiver has a more substantial structure than does the optical sight, the resulting deformation typically occurs in the optical sight. The deformation of the optical sight, in turn, can create inaccuracy in the aiming of the weapon.
Apparatus such as mounting rings have been developed to reduce the deformation of the optical sight when it is mounted to the rail. Such techniques are generally limited to relatively small-diameter, regularly configured optical sights. There remains a need for an approach for mounting an optical sight to a weapon which minimizes the likelihood of damage or unacceptable deformation to the optical sight. The present invention fulfills this need, and further provides related advantages.